Transcatheter stent and valve assembly

ABSTRACT

Valves constructed from low porosity leaflets are disclosed. The valves disclosed herein may be integrated into a variety of structures, such as valved conduits and transcatheter stents, and may be constructed of one or more layers. Embodiments herein are also directed to methods of using the same and methods of making the same.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.15/729,545, filed Oct. 10, 2017, entitled “Transcatheter Stent and ValveAssembly,” which claims priority from U.S. Provisional Application No.62/406,175, filed on Oct. 10, 2016, entitled “Transcatheter Stent andValve Assembly,” and U.S. Provisional Application No. 62/532,736, filedon Jul. 14, 2017, entitled “Transcatheter Stent and Valve Assembly,”each of which is incorporated by reference herein in its entirety.

SUMMARY

Various embodiments are directed to a valve including one or moreleaflets, wherein each leaflet is constructed from a material which hasa surface porosity of about 1% to less than 15%.

In some embodiments, a valve may include one or more leaflets, whereineach leaflet is constructed from more than one layer of a material. Insome embodiments, at least two layers of the material can be anisotropicwith orientations that are offset by an angle of at least 10 degrees.

In some embodiments, a valved conduit may include a conduit that has aninner surface and an outer surface, a valve that can be attached to theinner surface of the conduit at a plurality of attachment points,wherein the valve includes one or more leaflets, and wherein the one ormore leaflets are constructed from a material which has a surfaceporosity of about 1% to less than 15%.

In some embodiments, a valved conduit may include a conduit having aninner surface and an outer surface, a valve attached to the innersurface of the conduit at a plurality of attachment points, the valvemay further include one or more leaflets, wherein the one or moreleaflets are constructed from more than one layer of a material, whereat least two layers are anisotropic with orientations that are offset byan angle of at least 10 degrees.

In some embodiments, a valved conduit may include a fluoropolymerconduit having an inner surface and an outer surface, a valve attachedto the inner surface of the fluoropolymer conduit at a plurality ofattachment points. In some embodiments, the valve may further compriseone or more leaflets, wherein the one or more leaflets are constructedfrom at least two layers of a fluoropolymer which has a surface porosityof about 1% to about 7% and a total thickness of about 0.045 mm. In someembodiments, the at least two layers are anisotropic with orientationsthat offset by an angle of at least 10 degrees.

In some embodiments, a transcatheter stent may include a stent havingchevron shaped structures disposed in two annular rows opposing eachother, the stent may further include an inner surface and an outersurface and a collapsed configuration and an expanded configuration. Insome embodiments, a valve can be attached to the inner surface of thestent at a plurality of attachment points, each attachment point beingat a median vertex of the chevron shaped structure.

In some embodiments, a transcatheter stent may include a stent having aproximal portion and a distal portion, each portion may include aplurality of spindle-shaped structures, and an intermediate portionhaving chevron shaped structures disposed in annular rows opposing eachother.

In some embodiments, a transcatheter stent may include a stent havingchevron shaped structures disposed in two annular rows opposing eachother, the stent may further include an inner surface and an outersurface and a collapsed configuration and an expanded configuration. Insome embodiments, a valve can be attached to the inner surface of thestent at a plurality of attachment points, each attachment point beingat a median vertex of the chevron shaped structure, or along a memberwhich rotates during the transition between collapsed configuration andexpanded configuration.

In some embodiments, a transcatheter stent may include a stent havingchevron shaped structures disposed in two annular rows opposing eachother, the stent may further include an inner surface and an outersurface and a collapsed configuration and an expanded configuration. Insome embodiments, a valve can be attached to the inner surface of thestent at a plurality of attachment points, each attachment point beingat a median vertex of the chevron shaped structure. In some embodiments,the valve may further include one or more leaflets constructed from atleast two layers of a fluoropolymer, wherein the at least two layers areanisotropic with orientations that offset by an angle of at least 10degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a valved conduit in closed position. FIG. 1B shows avalved conduit in an open position

FIG. 2A shows a valved conduit in open position. FIG. 2B shows a valvedconduit in a closed position.

FIG. 3A is a schematic showing the position of a valve in relation to aconduit. FIG. 3B shows a valved conduit in closed position with thelengths illustrated in FIG. 3A superimposed over the valve components.

FIG. 4 is an illustration of a leaflet.

FIG. 5A shows a valved conduit that has been inverted such that thevalve is on an outward facing side of the conduit. FIG. 5B shows avalved conduit with the valve on an inner surface of the conduit.

FIG. 6A is a schematic illustrating a tapered dimple created between theleaflet and an inner surface of the conduit in a longitudinal view. FIG.6B is a schematic illustrating a tapered dimple created between theleaflet and an inner surface of the conduit in a cross-sectional view.

FIG. 7A depicts a valve in an inverted configuration. FIG. 7Billustrates a perpendicular cross section of the valve of FIG. 7A. FIG.7C illustrates a two-dimensional view of the valve in operableconfiguration where the conduit has been reverted such that the valve ison the inner surface of the conduit. FIG. 7D illustrates athree-dimensional view of the valve in operable configuration where theconduit has been reverted such that the valve is on the inner surface ofthe conduit.

FIG. 8A shows a perspective view of a fixing stencil. FIG. 8B showsanother perspective view of a fixing stencil.

FIG. 9A depicts a stent according to an embodiment. FIG. 9B depicts apair of opposing chevron shaped structures according to an embodiment.FIG. 9C depicts a single chevron structure with median and lateralvertices. FIG. 9D depicts the stent with a plurality of attachmentpoints in expanded configuration. FIG. 9E depicts the stent with aplurality of attachment points in collapsed configuration.

FIG. 10 illustrates a schematic design of a leaflet made from anon-stretchable material, according to an embodiment.

FIG. 11A shows a stent with a valve in an open position. FIG. 11B showsa stent with a valve in a closed position.

FIG. 12A shows a stent with a valved conduit in deployed configurationand crimped configuration, where the conduit and the valve arenon-stretchable. FIG. 12B shows a stent with a valve in an openconfiguration and a closed configuration.

FIG. 13 is a SEM image of a leaflet illustrating a material having anaverage pore area, an average pore diameter, and a surface porosity,according to an embodiment.

FIG. 14A is a SEM image of a Gore Preclude Membrane illustrating Side Aof a material having a surface porosity. FIG. 14B is a SEM image of aleaflet illustrating Side A of a material having a surface porosity.FIG. 14C is a SEM image of a Gore Preclude Membrane illustrating Side Bof a material having a surface porosity. FIG. 14D is a SEM image of aleaflet illustrating Side B of a material having a surface porosity.FIG. 14E depicts the quantification of the SEM images in FIGS. 14A, 14B,14C, and 14D.

FIG. 15A illustrates a leaflet having an ultimate tensile stressaccording to an embodiment compared to a Gore Preclude Membrane. FIG.15B illustrates a leaflet having a burst pressure according to anembodiment compared to a Gore Preclude Membrane. FIG. 15C illustrates aleaflet having a suture retention strength according to an embodimentcompared to a Gore Preclude Membrane. FIG. 15D illustrates a leaflethaving a suture retention 45 degree orientation according to anembodiment compared to a Gore Preclude Membrane.

FIG. 16A illustrates a leaflet having a bending modulus in MPa accordingto an embodiment compared to a Gore Preclude. FIG. 16B illustrates aleaflet having a bending modulus in N mm² according to an embodimentcompared to a Gore Preclude.

FIG. 17A depicts a leaflet having a membrane tension according to anembodiment compared to a Gore Preclude Membrane. FIG. 17B depicts aleaflet having a stress according to an embodiment compared to a GorePreclude Membrane.

FIG. 18A depicts Side A of a leaflet having reduced thrombogenicityaccording to an embodiment. FIG. 18B depicts Side B of a leaflet havingreduced thrombogenicity according to an embodiment. FIG. 18C depicts amagnified view of FIG. 18A. FIG. 18D depicts a magnified view of FIG.18B. FIG. 18E depicts Side A of a Gore Preclude Membrane havingthrombogenicity. FIG. 18F depicts Side B of a Gore Preclude Membranehaving thrombogenicity. FIG. 18G depicts a magnified view of FIG. 18E.FIG. 18H depicts a magnified view of FIG. 18F.

FIG. 19A illustrates a multi-layer conduit having a luminal surface withreduced thrombogenicity according to an embodiment. FIG. 19B illustratesa multi-layer conduit having an abluminal surface with reducedthrombogenicity according to an embodiment. FIG. 19C illustrate a GorePreclude Membrane having thrombogenicity. FIG. 19D illustrates a BARDImpra Conduit having thrombogenicity.

DETAILED DESCRIPTION

Before the invention is described, it is to be understood that thisinvention is not limited to the particular systems, methodologies orprotocols described, as these may vary. It is also to be understood thatthe terminology used herein is for the purpose of describing particularembodiments only, and is not intended to limit the scope of the presentdisclosure.

For the purpose of this disclosure, the term “plastically deformablematerial” means a material that may change its shape, size, or bothshape and size in response to a deforming force placed thereon, andwhich does not fully recover its original shape, size, or both shape andsize once the deforming force has been removed.

For the purpose of this disclosure, the term “elastic material” means amaterial that may change its shape, size, or both shape and size inresponse to a deforming force placed thereon, and which recovers itsoriginal shape, size, or both shape and size once the deforming forcehas been removed.

For the purpose of this disclosure, the term “yield strength” means thesmallest deforming force that, when applied to a material, will resultin a non-recoverable change in the shape, size, or both shape and sizeof the material.

For the purpose of this disclosure, the term “ultimate tensile strength”means the smallest deforming force that, when applied to a material,will result in a break or failure of the material.

As used herein, the term “about” means plus or minus 10% of thenumerical value of the number with which it is being used. Therefore,about 50% means in the range of 45% to 55%.

As used herein, the term “surface porosity” means the totaltwo-dimensional area of empty space in a given surface of a layer ofmaterial. Surface porosity is also referred to as surface percentporosity or pore area percent. Surface porosity is calculated bydividing the amount of empty space in a given two-dimensional area of alayer of material by the total two-dimensional area of that layer ofmaterial.

As used herein, the term “average pore area” means the average area ofthe pores in a layer of material having a plurality of pores. Theaverage pore area is calculated by adding the pore area of the pluralityof pores of a layer of material and dividing by the total number ofpores in that layer of material.

As used herein, the term “pore diameter” means the longest diameter of apore (major axis).

As used herein, the term “average pore diameter” means the averagediameter of the pores in a one-layered or multi-layered material havinga plurality of pores. The average pore diameter is calculated by addingthe pore diameter of the plurality of pores of the one-layered ormulti-layered material and dividing by the total number of porestherein.

As used herein, the term “total thickness” means the sum thickness of aconduit, a valve, or a leaflet having more than one layer of material.

As used herein, the term “rotate” means a movement which keeps a fixedpoint. This definition of rotation can apply within both two and threedimensions (in a plane and in space, respectively).

As used herein, the term “translation” means a movement which movesevery point of a figure of a space by the same amount in a givendirection.

As used herein, the term “non-stretching” means a material which has astrain less than 5%.

A valved conduit is a conduit having a valve disposed within it. Avalved conduit is typically mounted on a stent before deployment. Thereare two types of stents on which the valved conduits are ordinarilymounted: a self-expanding stent and a balloon-expandable stent. To placesuch valved conduits and stents into a delivery apparatus and ultimatelyinto a patient, the valved conduit and the stent must first be collapsedor crimped to reduce its circumferential size.

To date, the design and construction of these valved conduits havenecessitated the use of a stretchable material in order to accommodatethe change in shape that a conduit goes through between a collapsedstate (for introduction through a small vessel) and an expanded state(for function in the final deployed position). Disclosed herein aretranscatheter stents that substantially has same length between thecollapsed state and the expanded state and aid in use of non-stretchableconduits and valve structures.

Various embodiments are directed to valved conduits having leaflets thatdo not contact the wall of the conduit in open position (FIG. 1B). Asillustrated in FIG. 1A and FIG. 1B, an exemplary valved conduitencompassed by such embodiments may include a conduit 10 having an innersurface 11 and an outer surface 12. A valve 100 composed of one or moreleaflets may be disposed within the conduit 10 and attached to the innersurface 11 of the conduit 10. In open position (FIG. 1B), a sinus gap Gseparates the inner surface of the conduit 11 from the valve 100.

FIG. 2A and FIG. 2B illustrate an interior downstream, cross-sectionalview of an exemplary valve encompassed by FIG. 1A and FIG. 1B in anopen, FIG. 2A, and closed, FIG. 2B, configuration. In the open (FIG. 2A)configuration, fluid flows through the valve, forcing the fan portion ofa leaflet 201 towards the inner surface of the conduit. In the closedconfiguration (FIG. 2B) the fan portion of the leaflet 201 may form aclosure against fluid backflow. FIG. 2A and FIG. 2B show a conduit 20having an inner surface 21 and an outer surface 22, and a valve composedof one or more leaflets 201 that are attached to the inner surface 21 ofthe conduit 20. In open configuration (FIG. 2A), a sinus gap 202 iscreated between the leaflets 201 and the inner surface 21 of the conduit20 that allows the leaflets 201 to fully extend without contacting theinner surface 21 of the conduit 20. In embodiments such as thosedepicted in FIG. 2A and FIG. 2B in which the valve includes twoleaflets, at least a portion of the leaflets 201 may overlap along adiameter of the conduit 20 when in closed configuration (FIG. 2B),thereby substantially blocking flow of fluid through the conduit 20. Inembodiments in which the valve includes one leaflet, the leaflet maycontact the inner surface of the conduit opposite the attachment site ofthe valve, and in embodiments in which the valve includes three or moreleaflets, the leaflets may overlap at a longitudinal axis of the tube.

In some embodiments, a conduit has an attachment point on an innersurface of the conduit. In some embodiments, a valve is attached to theconduit at the attachment point. In some embodiments, the valve isattached to the conduit at one or more attachment points. In someembodiments, the valve is attached to the conduit at a plurality ofattachment points. In some embodiments, the vale is attached to theconduit at least one attachment point.

In some embodiments, the valve may be attached to the conduit bysuturing, welding, fusion, applying an adhesive, clamping, sintering,heating, chemical welding, static electric, frictional forces, lasering,and combinations thereof. Where the valve is attached to the conduit bywelding, fusion, adhesive, sintering, or the like which form a line ofattachment rather than a single point, the valve is considered to beattached to the conduit at a plurality of attachment points.

The sinus gap 202 between the inner surface 21 of the conduit 20 and theleaflets 201 can be created by any means. For example, in someembodiments, the width W of the leaflets 201 may be shorter than thelength of conduit between attachment points, D_(f). This arrangement isillustrated in FIG. 3A and FIG. 3B. FIG. 3A shows a simple diagram ofthe valve configuration in which the leaflet 301 of a valve encompassedby the embodiments described above is disposed within a conduit 30 suchthat the width, W (dashed line), of the leaflet 301 is shorter than theportion of the conduit, D_(f), between a first attachment point, f₁,connecting the leaflet 301 to the inner surface 31 of the conduit 30 anda second attachment point, f₂, connecting the leaflet to the innersurface 31 of the conduit 30. This valve configuration is furtherillustrated in FIG. 3B using the example valve depicted in FIG. 2B. Theportion of the conduit, D_(f), between the first attachment point, f₁,and the second attachment point, f₂, is longer than the width, W (dashedline), of the leaflet 301.

In some embodiments, a valve gap may be formed by the valve in a closedconfiguration. Specifically, as shown in FIG. 2B a multi-leaflet valveand at least a portion of a conduit inner surface may be disposed toform a valve gap 203 formed at the intersection of at least a portion ofthe inner surface of the conduit and a portion of the fan edge.

FIG. 4 is an illustration of a valve 44 unfolded on single plane withthe width, W, of the leaflet illustrated in FIG. 2B identified (dashedline). In some embodiments, the leaflet may have additional featuresillustrated in FIG. 4. Although FIG. 4 shows a valve 44 configured tocreate a two leaflets, 401 a and 401 b, a leaflet for a single leafletvalve or a leaflet for a three or four leaflet valve may include thesame elements in a similar configuration.

Each leaflet 401 a, 401 b may include an outer sinus edge 402 a, 402 b,an inner sinus edge 403 a, 403 b, and an open sinus edge 404 a, 404 b.In embodiments in which the leaflet includes two or more leaflets, theopen sinus edge 404 a, 404 b of each leaflet 401 a, 401 b may bycoextensive as illustrated in FIG. 4. In some embodiments, the valve 44may have a commissure 420 connecting the first leaflet 401 a and thesecond leaflet 401 b. In particular embodiments, the commissure 420 maybe a perpendicular intersection connecting each inner sinus edge 403 a,403 b with the meeting point of the open sinus edges 404 a, 404 b,creating a linear connection perpendicular to the open sinus edges 404a, 404 b and at an angle to the inner sinus edges 403 a, 403 b.

In some embodiments, each leaflet 401 a, 401 b may further include a fan410 a, 410 b having a fan edge 411 a, 411 b extending beyond the opensinus edge 404 a, 404 b away from the outer sinus edge 401 a, 401 b andinner sinus edge 402 a, 402 b. The fan 410 a, 410 b may allow theleaflets of the valve to contact one another or overlap when the valveis in the closed position (see FIG. 3B) stopping flow of fluid throughthe valve. The fan 410 a, 410 b may have any shape, and in certainembodiments, the fan 410 a, 410 b may have a curved shape with a widesection on one side of the leaflet and a narrow section on the oppositeside of the leaflet. In some embodiments, the narrow section of the fan410 a of a first leaflet 401 a may connect to a narrow section of thefan 410 b of the second leaflet 401 b at the commissure 420, and inparticular embodiments, the narrow section of the fan 410 a of a firstleaflet 401 a may connect to a narrow section of the second leaflet 401b at the commissure 420 at the connection point of the open sinus edges404 a, 404 b.

FIG. 5A and FIG. 5B show a leaflet 54 such as that described in FIG. 4attached to a conduit 50. In FIG. 5A, the conduit 50 is inverted suchthat the leaflet 54 is disposed on the outside of the conduit 50, andthe conduit 50 is reverted such that the leaflet 54 is inside theconduit 50. Thus, an inner surface 51 is on the outside of the conduit50 in FIG. 5A, and the inner surface 51 is inside the conduit 50 in FIG.5B. An outer surface 52 is on the inside of the conduit 50 in FIG. 5A,and the outer surface 52 is outside the conduit 50 in FIG. 5B. Theleaflet 54 may be attached to the inner surface 51 of the conduit 50 atthe outer sinus edge 502 a and 502 b and the inner sinus edge 503 a and503 b (503 a is on the opposite side of the conduit 54). Each of theouter sinus edges 502 a, 502 b and inner sinus edge 503 a, 503 b may beattached to the conduit by a substantially fluid impervious connectionsuch as, for example, suturing (as shown), fusion, applying an adhesive,or welding. The commissure 520 may also be attached to the inner surface51 of the conduit 50 by, for example, suturing (as shown), applying anadhesive, or welding. The open sinus edge 504 a, 504 b are not attachedto the conduit 50, and remain open to fluids flowing through the conduit50. The opening creates a sinus 530 a, 530 b between the inner surface51 of the conduit 50 and each leaflet 501 a, 501 b, and each open sinusedge 504 a, 504 b.

FIG. 6A and FIG. 6B are a three-dimensional representation of a leaflet601 (dark shading) on an inverted conduit 60 to show the sinus 630created by the leaflet 601. FIG. 6A is a longitudinal view and FIG. 6Bis a cross-sectional view. As in FIG. 5A, the leaflet 601 is attached tothe conduit at the outer sinus edge 602 and inner sinus edge 603 by asubstantially fluid impervious connection such as, for example,suturing, applying an adhesive, or welding. A tapered dimple 65 in theconduit 60 underlying the leaflet 601 provides the conduit side of thesinus 630 and allows the valve to achieve the configuration illustratedin FIG. 5B when the conduit 60 is returned to its original shape (i.e.reverted such that the outer surface 62 of the conduit 60 is on an outersurface of the structure). Because the width of the leaflet 601 changesalong its length, the degree to which the conduit must bend also changesalong the length of the conduit 60.

This arrangement is further illustrated in FIG. 7A, FIG. 7B, FIG. 7C,and FIG. 7D. In FIG. 7A, a valve is in an inverted configuration andshows a leaflet 701 of the valve disposed within a conduit 70 such thatthe width, W (dashed line), of the leaflet 701 is shorter than theportion of the conduit, D_(f), between a first attachment point, f₁ anda second attachment point, f₂, connecting the leaflet 701 to the innersurface of the conduit 70. FIG. 7B is a perpendicular cross section ofthe valve of FIG. 7A illustrating the tapered dimple 75. B is the lengthof the leaflet 701. W_(d) depth of the dimple 75, i.e. the depth of thegap between the leaflet 701 and the conduit 70, which, as illustratedvaries with B from the open edge 704 of the leaflet 701 to a point wherethe outer sinus edge 702 and the inner sinus edge 703 meet (see FIG.7D). FIG. 7C and FIG. 7D show the valve in operable configuration wherethe conduit has been reverted such that the valve is on the innersurface of the conduit 70 and conduit 70 has retained its cylindricalshape. The leaflet 701, which has an open edge 704 width, W, that isless than the circumference of the conduit 70 between attachment pointsmay be suspended below the inner surface of the conduit 70 by a depth,W_(d), which varies with the length, B, of the leaflet 701 creating asinus 730. With reference to FIG. 7D, in some embodiments, the leaflet701 may have a substantially triangular shape. Therefore, the leafletwidth, W, may also vary with the length, B, of the leaflet 701.

A valve having leaflets as described and discussed above may reduce thecontact of the leaflets and, in some embodiments, fans attached to theopen sinus edge, with the inner surface of the conduit when the valve isin open configuration. Reduced contact with the inner surface of theconduit decreases the likelihood that the valve will stick in openconfiguration and may also reduce wear on the leaflet over many cycles.Thus, the valves of various embodiments may provide improved long termuse when implanted as part of a medical device. For example, in someembodiments, the valves described above may be used as a shunt forconnecting of the right ventricle to the pulmonary artery following aNorwood operation, as frequently performed for the treatment ofsingle-functional-ventricle-disorders such as Hypoplastic Left HeartSyndrome. In other embodiments, the valves described above may be usedfor the correction or reconstruction of the right ventricle outflowtract (RVOT) for congenital heart disorders such as tetralogy of Fallot,Truncus Arterious, DextroTransposition of the Great Arteries, PulmonaryAtresia of Intact Ventricular Septum, or Aortic Valvular Disease. Instill other embodiments, the valves described above may be incorporatedinto a stent and deployed as artificial valves in adult and pediatricpatients.

The conduit 10, 20, 30, 50, 60, 70, and 1101 of various embodiments, andthe valve 100, 44, 1102 or leaflet 201, 301, 54, 601, 701, 801 may beconstructed from a material. In some embodiments, the material comprisesany biocompatible and hemocompatible polymer. In some embodiments, thematerial can be a fluoropolymer. In some embodiments, the material canbe a polymer. In some embodiments, the material can bepolytetrafluoroethylene, expanded polytetrafluoroethylene, polyester,polyethylene terephthalate, polydimethylsiloxane, polyurethane, andcombinations thereof. In some embodiments, the material may be extruded.In some embodiments, the material may be an extruded fluoropolymer. Insome embodiments, the material may be an extruded polymer. In someembodiments, the fluoropolymer can be polytetrafluoroethylene, expandedpolytetrafluoroethylene, and combinations thereof. In some embodiments,the polymer can be polyester, polyethylene terephthalate,polydimethylsiloxane, polyurethane, and combinations thereof. In someembodiments, the material may be a fluoropolymer coated with a bioactivecoating. In some embodiments, the material may be surface-modified toinclude a surface coating or a bioactive material. In some embodiments,the material may be a polymer coated with a bioactive coating. In someembodiments, the material may be surface-modified to include a surfacecoating or a bioactive material. The surface coating or bioactivematerial may be an anti-coagulant coating or an anti-coagulant materialthat promotes biocompatibility such as, for example, coumadin, heparin,a heparin derivative, a Factor Xa inhibitor, a direct thrombininhibitor, hementin, sintered porous titanium microspheres, a carboncoating, or combinations thereof.

In some embodiments, the material is non-stretchable. In someembodiments, the material is non-stretchable biocompatible andhemocompatible. Non-limiting examples of non-stretchable biocompatibleand hemocompatible material that can be used to make the conduits orvalve are polytetrafluoroethylene (PTFE), expandedpolytetrafluoroethylene (ePTFE), polyethylene terephthalate (PET),polydimethyl siloxane (PDMS), polyethylene (PE), polypropylene (PP),polyesters, polycarbonates, polyvinyl chloride (PVC), hydrogels, and thelike. In some embodiments, the biocompatible and hemocompatible materialmay be a polymer coated with a bioactive coating. In some embodiments,the biocompatible and hemocompatible polymer may be surface-modified toinclude a bioactive material.

In some embodiments, the conduit, the valve, or the leaflet are madefrom a layer of the material. In some embodiments, the conduit, thevalve, or the leaflet are made from multiple layer of the material. Insome embodiments, the conduit, the valve, or the leaflet are made frommore than one material. In some embodiments, the conduit, the valve, orthe leaflet are made from one or more layers of the material. In someembodiments, the conduit, the valve, or the leaflet are made from atleast two layers of the material. In some embodiments, the conduit, thevalve, or the leaflet are made from a first layer of a first materialand a second layer of a second material.

The conduit 10, 20, 30, 50, 60, 70, and 1101 described herein maygenerally be flexible, and the size of the conduit of variousembodiments may vary depending on the intended use of the valve. In someembodiments, the conduit may have a diameter in a range of about 40 mmto about 15 mm, about 25 mm to about 2 mm, about 20 mm to about 2 mm,about 15 mm to about 2 mm, about 10 mm to about 2 mm, about 8 mm toabout 3 mm, about 5 mm to about 3 mm, or any range or individualdiameter encompassed by these example ranges. In other embodiments, theconduit may have a diameter in a range of about 40 mm to about 15 mm,about 25 mm to about 5 mm, about 20 mm to about 8 mm, about 15 mm toabout 10 mm, or any range or individual diameter encompassed by theseexample ranges. In some embodiments, the conduit may have a diameter ina range of about 2 mm to about 40 mm, about 2 mm to about 30 mm, about 2mm to about 20 mm, about 2 mm to about 10 mm, about 2 mm to about 5 mm.In some embodiments, the conduit may have a diameter in a range of about5 mm to about 40 mm, about 10 mm to about 40 mm, about 20 mm to about 40mm. In some embodiments, the conduit diameter is 2 mm. In someembodiments, the conduit diameter is 3 mm. In some embodiments, theconduit diameter is 4 mm. In some embodiments, the conduit diameter is 5mm. In some embodiments, the conduit diameter is 6 mm. In someembodiments, the conduit diameter is 7 mm. In some embodiments, theconduit diameter is 8 mm.

In some embodiment, the conduit may have a thicknesses in a range ofabout 0.05 mm to about 0.5 mm, about 0.5 mm to about 2.0 mm, about 0.5mm to about 1.5 mm, or any range or individual thickness encompassed bythese example ranges. In some embodiments, the conduit thickness is 0.05mm. In some embodiments, the conduit thickness is 0.5 mm. In someembodiments, the conduit thickness is 1.5 mm. In some embodiments, theconduit thickness is 2 mm. In some embodiments, the conduit thickness is1 mm.

In some embodiments, the conduit comprises more than one layer of thematerial. In some embodiments, the conduit comprises multiple materials.For example, the conduit may comprise a material having a first yieldstrength and first ultimate tensile strength and may be impregnated witha second material having a second yield strength and/or second ultimatetensile strength. In some embodiments, the conduit may be fabricatedfrom two or more elastic or plastically deformable materials woventogether.

In embodiments in which the conduit includes more than one layer of thematerial, each layer of a multi-layer conduit may be composed of thesame material. In other embodiments, each layer of a multi-layer conduitmay be composed of a different material. In further embodiments, eachlayer of a multi-layer conduit may be composed of a materialcharacterized by different mechanical properties. For example, an innerlayer of a multi-layer conduit may include a material having a firstyield strength and a first ultimate tensile strength and an outer layerthat may include a second material having a second yield strength and/ora second ultimate tensile strength. The first yield strength may begreater than, about equal to, or less than the second yield strength.The first ultimate tensile strength may be greater than, about equal to,or less than the second ultimate tensile strength. Alternatively, aninner layer may include an elastic or plastically deformable materialand an outer layer may include an inelastic or frangible material.

In some embodiments, the conduit is constructed from one or more layersof a material having a surface porosity. In some embodiments, thesurface porosity of one or more layers is about 1%. In some embodiments,the surface porosity of one or more layers is about 2%. In someembodiments, the surface porosity of one or more layers is about 3%. Insome embodiments, the surface porosity of one or more layers is about4%. In some embodiments, the surface porosity of one or more layers isabout 5%. In some embodiments, the surface porosity of one or morelayers is about 10%. In some embodiments, the surface porosity of one ormore layers is about 15%. In some embodiments, the surface porosity ofone or more layers is about 20%. In some embodiments, the surfaceporosity of one or more layers is about 30%. In some embodiments, thesurface porosity of one or more layers is about 40%. In someembodiments, the surface porosity of one or more layers is about 50%. Insome embodiments, the surface porosity of one or more layers is about60%. In some embodiments, the surface porosity of one or more layers isabout 70%. In some embodiments, the surface porosity of one or morelayers is about 80%. In some embodiments, the surface porosity of one ormore layers is about 90%. In some embodiments, the surface porosity ofone or more layers is less than 20%. In some embodiments, the surfaceporosity of one or more layers is less than 15%. In some embodiments,the surface porosity of one or more layers is less than 10%. In someembodiments, the surface porosity of one or more layers is less than 5%.In some embodiments, the surface porosity of one or more layers is lessthan 4%. In some embodiments, the surface porosity of one or more layersis less than 3%. In some embodiments, the surface porosity of one ormore layers is less than 2%. In some embodiments, the surface porosityof one or more layers is less than 1%. In some embodiments, the surfaceporosity of one or more layers is greater than 20%. In some embodiments,the surface porosity of one or more layers is greater than 30%. In someembodiments, the surface porosity of one or more layers is greater than40%. In some embodiments, the surface porosity of one or more layers isgreater than 50%. In some embodiments, the surface porosity of one ormore layers is greater than 60%. In some embodiments, the surfaceporosity of one or more layers is greater than 70%. In some embodiments,the surface porosity of one or more layers is greater than 80%. In someembodiments, the surface porosity of one or more layers is greater than90%. In some embodiments, the surface porosity of one or more layers isin a range of about 1% to about 20%. In some embodiments, the surfaceporosity of one or more layers is in a range of about 1% to about 15%.In some embodiments, the surface porosity of one or more layers is in arange of about 1% to about 10%. In some embodiments, the surfaceporosity of one or more layers is in a range of about 1% to about 5%. Insome embodiments, the surface porosity of one or more layers is in arange of about 1% to about 4%. In some embodiments, the surface porosityof one or more layers is in a range of about 1% to about 3%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 1% to about 2%. In some embodiments, the surface porosity of oneor more layers is in a range of about 2% to about 20%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 3% to about 20%. In some embodiments, the surface porosity of oneor more layers is in a range of about 4% to about 20%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 5% to about 20%. In some embodiments, the surface porosity of oneor more layers is in a range of about 10% to about 20%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 15% to about 20%. In some embodiments, the surface porosity of oneor more layers is in a range of about 2% to about 15%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 3% to about 10%. In some embodiments, the surface porosity of oneor more layers is in a range of about 4% to about 10%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 5% to about 10%. In some embodiments, the surface porosity of oneor more layers is in a range of about 5% to about 20%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 5% to about 15%. In some embodiments, the surface porosity of oneor more layers is in a range of about 5% to about 10%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 20% to about 90%. In some embodiments, the surface porosity of oneor more layers is in a range of about 20% to about 80%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 20% to about 70%. In some embodiments, the surface porosity of oneor more layers is in a range of about 20% to about 60%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 20% to about 50%. In some embodiments, the surface porosity of oneor more layers is in a range of about 20% to about 40%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 20% to about 30%. In some embodiments, the surface porosity of oneor more layers is in a range of about 30% to about 90%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 40% to about 90%. In some embodiments, the surface porosity of oneor more layers is in a range of about 50% to about 90%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 60% to about 90%. In some embodiments, the surface porosity of oneor more layers is in a range of about 70% to about 90%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 80% to about 90%. In some embodiments, the surface porosity of oneor more layers is in a range of about 30% to about 80%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 30% to about 70%. In some embodiments, the surface porosity of oneor more layers is in a range of about 30% to about 60%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 30% to about 50%. In some embodiments, the surface porosity of oneor more layers is in a range of about 30% to about 40%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 40% to about 80%. In some embodiments, the surface porosity of oneor more layers is in a range of about 50% to about 80%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 60% to about 80%. In some embodiments, the surface porosity of oneor more layers is in a range of about 70% to about 80%. In someembodiments, the surface porosity of one or more layers is in a range ofabout 40% to about 70%. In some embodiments, the surface porosity is ina range of about 40% to about 60%. In some embodiments, the surfaceporosity of one or more layers is in a range of about 40% to about 50%.In some embodiments, the surface porosity of one or more layers is in arange of about 50% to about 70%. In some embodiments, the surfaceporosity of one or more layers is in a range of about 60% to about 70%.

Conduits composed of multiple layers may have expansion capabilitiesdepending on the material properties of the multiple layers. In someembodiments, a conduit comprising a biodegradable outer layer and anelastic or plastically deformable inner layer may be expanded due to theforce of a fluid flowing therein but only after the outer layer hasdegraded. In some embodiments, a conduit having an inelastic orfrangible outer layer and an elastic or plastically deformable innerlayer may remain in an unexpanded state until sufficient force, forexample, supplied by an inserted expansion device, is applied internallyto rupture the outer layer and thus permit the inner layer to expand.

In some embodiments, the conduit materials, formulations, and/ormechanical properties may be constant over the longitudinal dimension ofthe conduit. In some embodiments, the conduit materials, formulations,and/or mechanical properties of the conduit may vary along the length orany partial length of the conduit. Conduits having multiple branches mayhave mechanical properties that differ between the branches and/or amain cylindrical tube of the conduit.

In certain embodiments, the conduits described above may includeadditional components. In some embodiments, the conduit may include astent that is attached to or encapsulated by the material of theconduit, or an inner layer may include a stent while an outer layer mayinclude an elastic or plastically deformable material. In someembodiments, a conduit may be composed of a biodegradable outer layerand an elastic or plastically deformable inner layer. In some furtherexamples, a multi-layer conduit may include a first inner layercomprising a woven material and a second outer layer comprising a wovenmaterial. It may be understood that the woven material composing theinner layer may be the same as the woven material composing the outerlayer. Alternatively, the woven material composing the inner layer maydiffer from the woven material composing the outer layer.

In some embodiments, the conduit may comprise a valve. In someembodiments, the valved conduit may include a conduit having a firstconduit layer having an inner surface in physical communication with anouter surface of a second conduit layer and the valve is disposed withinthe second conduit layer. As one example of such a multi-layer valvedconduit, the first conduit layer may be composed of a first plasticallydeformable material having a yield strength of about 0.1 MPa to about 4MPa, and the second conduit layer may be composed of the sameplastically deformable material as the first layer. In an alternativeexample, the multi-layer valved conduit may be composed of a firstconduit layer having a first plastically deformable material having ayield strength of about 0.1 MPa to about 4 MPa, and a second conduitlayer composed of a second material that may differ from the firstmaterial. In still another example, the valved conduit may have a firstconduit layer composed of a woven material, a second conduit layercomposed of a woven material, or both the first conduit layer and thesecond conduit layer may each be composed of a woven material. In someembodiments of the multi-layer valved conduit, the first conduit layermay be biodegradable. In some alternative embodiments of a multi-layervalved conduit, the first conduit layer may include a non-plasticallydeformable material. In yet another embodiment, the multi-layer valvedconduit may include a stent as part of the second conduit layer.

In some embodiments, the conduit has a yield strength. In someembodiments, the yield strength is about 0.1 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.2 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.3 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.4 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.5 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.7 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.8 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.9 MPa to about 4 MPa. In someembodiments, the yield strength is about 1 MPa to about 4 MPa. In someembodiments, the yield strength is about 0.1 MPa to about 0.2 MPa. Insome embodiments, the yield strength is about 0.1 MPa to about 0.3 MPa.In some embodiments, the yield strength is about 0.1 MPa to about 0.4MPa. In some embodiments, the yield strength is about 0.1 MPa to about0.5 MPa. In some embodiments, the yield strength is about 0.1 MPa toabout 0.6 MPa. In some embodiments, the yield strength is about 0.1 MPato about 0.7 MPa. In some embodiments, the yield strength is about 0.1MPa to about 0.8 MPa. In some embodiments, the yield strength is about0.1 MPa to about 0.9 MPa. In some embodiments, the yield strength isabout 0.1 MPa to about 1 MPa. In some embodiments, the yield strength isabout 0.1 MPa to about 12 MPa. In some embodiments, the yield strengthis about 0.1 MPa to about 11 MPa. In some embodiments, the yieldstrength is about 0.1 MPa to about 10 MPa. In some embodiments, theyield strength is about 0.1 MPa to about 9 MPa. In some embodiments, theyield strength is about 0.1 MPa to about 8 MPa. In some embodiments, theyield strength is about 0.1 MPa to about 7 MPa. In some embodiments, theyield strength is about 0.1 MPa to about 6 MPa. In some embodiments, theyield strength is about 0.1 MPa to about 5 MPa. In some embodiments, theyield strength is about 0.2 MPa to about 12 MPa. In some embodiments,the yield strength is about 0.2 MPa to about 11 MPa. In someembodiments, the yield strength is about 0.2 MPa to about 10 MPa. Insome embodiments, the yield strength is about 0.2 MPa to about 9 MPa. Insome embodiments, the yield strength is about 0.2 MPa to about 8 MPa. Insome embodiments, the yield strength is about 0.2 MPa to about 7 MPa. Insome embodiments, the yield strength is about 0.2 MPa to about 6 MPa. Insome embodiments, the yield strength is about 0.2 MPa to about 5 MPa. Insome embodiments, the yield strength is about 0.3 MPa to about 12 MPa.In some embodiments, the yield strength is about 0.3 MPa to about 11MPa. In some embodiments, the yield strength is about 0.3 MPa to about10 MPa. In some embodiments, the yield strength is about 0.3 MPa toabout 9 MPa. In some embodiments, the yield strength is about 0.3 MPa toabout 8 MPa. In some embodiments, the yield strength is about 0.3 MPa toabout 7 MPa. In some embodiments, the yield strength is about 0.3 MPa toabout 6 MPa. In some embodiments, the yield strength is about 0.3 MPa toabout 5 MPa. In some embodiments, the yield strength is about 0.4 MPa toabout 12 MPa. In some embodiments, the yield strength is about 0.4 MPato about 11 MPa. In some embodiments, the yield strength is about 0.4MPa to about 10 MPa. In some embodiments, the yield strength is about0.4 MPa to about 9 MPa. In some embodiments, the yield strength is about0.4 MPa to about 8 MPa. In some embodiments, the yield strength is about0.4 MPa to about 7 MPa. In some embodiments, the yield strength is about0.4 MPa to about 6 MPa. In some embodiments, the yield strength is about0.4 MPa to about 5 MPa. In some embodiments, the yield strength is about0.5 MPa to about 12 MPa. In some embodiments, the yield strength isabout 0.5 MPa to about 11 MPa. In some embodiments, the yield strengthis about 0.5 MPa to about 10 MPa. In some embodiments, the yieldstrength is about 0.5 MPa to about 9 MPa. In some embodiments, the yieldstrength is about 0.5 MPa to about 8 MPa. In some embodiments, the yieldstrength is about 0.5 MPa to about 7 MPa. In some embodiments, the yieldstrength is about 0.5 MPa to about 6 MPa. In some embodiments, the yieldstrength is about 0.5 MPa to about 5 MPa. In some embodiments, the yieldstrength is about 0.6 MPa to about 12 MPa. In some embodiments, theyield strength is about 0.6 MPa to about 11 MPa. In some embodiments,the yield strength is about 0.6 MPa to about 10 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 9 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 8 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 7 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 6 MPa. In someembodiments, the yield strength is about 0.6 MPa to about 5 MPa. In someembodiments, the yield strength is about 0.7 MPa to about 12 MPa. Insome embodiments, the yield strength is about 0.7 MPa to about 11 MPa.In some embodiments, the yield strength is about 0.7 MPa to about 10MPa. In some embodiments, the yield strength is about 0.7 MPa to about 9MPa. In some embodiments, the yield strength is about 0.7 MPa to about 8MPa. In some embodiments, the yield strength is about 0.7 MPa to about 7MPa. In some embodiments, the yield strength is about 0.7 MPa to about 6MPa. In some embodiments, the yield strength is about 0.7 MPa to about 5MPa. In some embodiments, the yield strength is about 0.8 MPa to about12 MPa. In some embodiments, the yield strength is about 0.8 MPa toabout 11 MPa. In some embodiments, the yield strength is about 0.8 MPato about 10 MPa. In some embodiments, the yield strength is about 0.8MPa to about 9 MPa. In some embodiments, the yield strength is about 0.8MPa to about 8 MPa. In some embodiments, the yield strength is about 0.8MPa to about 7 MPa. In some embodiments, the yield strength is about 0.8MPa to about 6 MPa. In some embodiments, the yield strength is about 0.8MPa to about 5 MPa. In some embodiments, the yield strength is about 0.9MPa to about 12 MPa. In some embodiments, the yield strength is about0.9 MPa to about 11 MPa. In some embodiments, the yield strength isabout 0.9 MPa to about 10 MPa. In some embodiments, the yield strengthis about 0.9 MPa to about 9 MPa. In some embodiments, the yield strengthis about 0.9 MPa to about 8 MPa. In some embodiments, the yield strengthis about 0.9 MPa to about 7 MPa. In some embodiments, the yield strengthis about 0.9 MPa to about 6 MPa. In some embodiments, the yield strengthis about 0.9 MPa to about 5 MPa. In some embodiments, the yield strengthis about 1 MPa to about 12 MPa. In some embodiments, the yield strengthis about 1 MPa to about 11 MPa. In some embodiments, the yield strengthis about 1 MPa to about 10 MPa. In some embodiments, the yield strengthis about 1 MPa to about 9 MPa. In some embodiments, the yield strengthis about 1 MPa to about 8 MPa. In some embodiments, the yield strengthis about 1 MPa to about 7 MPa. In some embodiments, the yield strengthis about 1 MPa to about 6 MPa. In some embodiments, the yield strengthis about 1 MPa to about 5 MPa. In some embodiments, the yield strengthis about 2 MPa to about 12 MPa. In some embodiments, the yield strengthis about 2 MPa to about 11 MPa. In some embodiments, the yield strengthis about 2 MPa to about 10 MPa. In some embodiments, the yield strengthis about 2 MPa to about 9 MPa. In some embodiments, the yield strengthis about 2 MPa to about 8 MPa. In some embodiments, the yield strengthis about 2 MPa to about 7 MPa. In some embodiments, the yield strengthis about 2 MPa to about 6 MPa. In some embodiments, the yield strengthis about 2 MPa to about 5 MPa. In some embodiments, the yield strengthis about 3 MPa to about 12 MPa. In some embodiments, the yield strengthis about 3 MPa to about 11 MPa. In some embodiments, the yield strengthis about 3 MPa to about 10 MPa. In some embodiments, the yield strengthis about 3 MPa to about 9 MPa. In some embodiments, the yield strengthis about 3 MPa to about 8 MPa. In some embodiments, the yield strengthis about 3 MPa to about 7 MPa. In some embodiments, the yield strengthis about 3 MPa to about 6 MPa. In some embodiments, the yield strengthis about 3 MPa to about 5 MPa. In some embodiments, the yield strengthis about 4 MPa to about 12 MPa. In some embodiments, the yield strengthis about 4 MPa to about 11 MPa. In some embodiments, the yield strengthis about 4 MPa to about 10 MPa. In some embodiments, the yield strengthis about 4 MPa to about 9 MPa. In some embodiments, the yield strengthis about 4 MPa to about 8 MPa. In some embodiments, the yield strengthis about 4 MPa to about 7 MPa. In some embodiments, the yield strengthis about 4 MPa to about 6 MPa. In some embodiments, the yield strengthis about 4 MPa to about 5 MPa. In some embodiments, the yield strengthis about 5 MPa to about 12 MPa. In some embodiments, the yield strengthis about 5 MPa to about 11 MPa. In some embodiments, the yield strengthis about 5 MPa to about 10 MPa. In some embodiments, the yield strengthis about 5 MPa to about 9 MPa. In some embodiments, the yield strengthis about 5 MPa to about 8 MPa. In some embodiments, the yield strengthis about 5 MPa to about 7 MPa. In some embodiments, the yield strengthis about 5 MPa to about 6 MPa. In some embodiments, the yield strengthis about 6 MPa to about 12 MPa. In some embodiments, the yield strengthis about 6 MPa to about 11 MPa. In some embodiments, the yield strengthis about 6 MPa to about 10 MPa. In some embodiments, the yield strengthis about 6 MPa to about 9 MPa. In some embodiments, the yield strengthis about 6 MPa to about 8 MPa. In some embodiments, the yield strengthis about 6 MPa to about 7 MPa. In some embodiments, the yield strengthis about 7 MPa to about 12 MPa. In some embodiments, the yield strengthis about 7 MPa to about 11 MPa. In some embodiments, the yield strengthis about 7 MPa to about 10 MPa. In some embodiments, the yield strengthis about 7 MPa to about 9 MPa. In some embodiments, the yield strengthis about 7 MPa to about 8 MPa. In some embodiments, the yield strengthis about 8 MPa to about 12 MPa. In some embodiments, the yield strengthis about 8 MPa to about 11 MPa. In some embodiments, the yield strengthis about 8 MPa to about 10 MPa. In some embodiments, the yield strengthis about 8 MPa to about 9 MPa. In some embodiments, the yield strengthis about 9 MPa to about 12 MPa. In some embodiments, the yield strengthis about 9 MPa to about 11 MPa. In some embodiments, the yield strengthis about 9 MPa to about 10 MPa. In some embodiments, the yield strengthis about 10 MPa to about 12 MPa. In some embodiments, the yield strengthis about 10 MPa to about 11 MPa. In some embodiments, the yield strengthis about 0.1 MPa. In some embodiments, the yield strength is about 0.2MPa. In some embodiments, the yield strength is about 0.3 MPa. In someembodiments, the yield strength is about 0.4 MPa. In some embodiments,the yield strength is about 0.5 MPa. In some embodiments, the yieldstrength is about 0.6 MPa. In some embodiments, the yield strength isabout 0.7 MPa. In some embodiments, the yield strength is about 0.8 MPa.In some embodiments, the yield strength is about 0.9 MPa. In someembodiments, the yield strength is about 1 MPa. In some embodiments, theyield strength is about 2 MPa. In some embodiments, the yield strengthis about 3 MPa. In some embodiments, the yield strength is about 4 MPa.In some embodiments, the yield strength is about 5 MPa. In someembodiments, the yield strength is about 6 MPa. In some embodiments, theyield strength is about 7 MPa. In some embodiments, the yield strengthis about 8 MPa. In some embodiments, the yield strength is about 9 MPa.In some embodiments, the yield strength is about 10 MPa. In someembodiments, the yield strength is about 11 MPa. In some embodiments,the yield strength is about 12 MPa.

The valve 100, 44, 1102 or leaflet 201, 301, 54, 601, 701, and 801 mayhave a thickness of about 0.05 mm to about 0.3 mm in variousembodiments, and this thickness may vary within the valve. In someembodiments, the valve may comprise a material having a a thickness ortotal thickness of about 0.05 mm to about 0.3 mm, about 0.1 mm to about0.3 mm, about 0.15 mm to about 0.3 mm, about 0.2 mm to about 0.3 mm,about 0.25 mm to about 0.3 mm, about 0.05 mm to about 0.25 mm, about 0.1mm to about 0.25 mm, about 0.2 mm to about 0.25 mm, about 0.05 mm toabout 0.2 mm, about 0.1 mm to about 0.2 mm, about 0.15 mm to about 0.2mm, or a value within any of these range. For example, in someembodiments, the sinus portion of the leaflet may have a greaterthickness than the fan portion or the fan portion may have a greaterthickness than the sinus portion of the leaflet. The thickness of thevalve may be selected to provide sufficient flexibility to allow thevalve to obtain the open and closed configurations under the pressure ofthe flow of fluid through the conduit. The dimensions of each leafletmay vary depending on the diameter of the conduit and the number ofleaflets making up the valve. For example with reference to FIG. 7D, invarious embodiments, ratio the length, B, of a leaflet 701, and thewidth, W, leaflet may be about 0.2 to about 2, about 0.3 to about 2,about 0.4 to about 2, about 0.5 to about 2, about 0.6 to about 2, about0.75 to about 2, about 1 to about 2, about 1 to about 1, or any ratiotherebetween or any ratio encompassed by these example ratios. In someembodiments, the ratio of the width of the leaflet to a portion of theconduit circumference between the attachment points may be about 0.63 toabout 1, about 0.7 to about 1, about 0.5 to about 1, or any ratiotherebetween or any ratio encompassed by these example ratios. The ratioof the width, W, the leaflet 701 to the diameter of the conduit may beabout 0.02 to about 3, about 0.05 to about 3, about 0.08 to about 3,about 0.1 to about 3, about 0.2 to about 3, about 0.5 to about 3, about1 to about 3, about 0.9 to about 1.7, or any ratio therebetween or anyratio encompassed by these example ratios. In embodiments, including acommissure 420 (FIG. 4) i.e. valves having more than one leaflet, theratio between a length of the commissure 420 and the width, W, of theleaflet 401, may be about 0.05 to about 2, about 0.1 to about 2, about0.2 to about 2, about 0.3 to about 2, about 0.5 to about 2, or any ratiotherebetween or any ratio encompassed by these example ratios. The ratioof the inner sinus edge 703 the leaflet 701 to the width, W, of theleaflet 701 may be about 0.2 to about 2.5, about 0.3 to about 2.5, about0.4 to about 2.5, about 0.5 to about 2.5, about 0.6 to about 2.5, about0.75 to about 2.5, about 1 to about 2.5, about 1 to about 1, or anyratio therebetween or any ratio encompassed by these example ratios.

In various such embodiments, the width, W, of the leaflet 701 may beabout 1 mm to about 10 mm, about 2 mm to about 7 mm, about 2 mm to about5 mm, about 20 mm to about 40 mm, about 10 mm to about 30 mm, or anyindividual width or range encompassed by these example widths. Thelength, B, of the leaflet 701 may be about 5 mm to about 40 mm, about 5mm to about 30 mm, about 8 mm to about 25 mm, about 10 mm to about 20mm, or any individual length, B, or range encompassed by these examplelengths. The length of the inner sinus edge 703 about outer sinus edge704 may each, individually, be about 5 mm to about 45 mm, about 5 mm toabout 35 mm, about 8 mm to about 30 mm, about 10 mm to about 20 mm, orany individual length or range encompassed by these example lengths. Insome embodiments, multiple leaflet valves may have no commissure, and inother embodiments, multiple leaflet valves may have a commissure havinga length of about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.3 mm,about 0.5 mm, about 0.8 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm,about 4.0 mm, about 6.0 mm, about 8.0 mm, about 10.0 mm, about 12.0 mm,or any range encompassing these example lengths.

Although FIG. 2A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4, FIG. 5A, FIG. 5B,FIG. 6A, FIG. 6B, FIG. 7A, FIG. 7B, FIG. 7C, and FIG. 7D illustratevalve structures composed of one or two leaflets, the valve of otherembodiments may be composed of any number of leaflets. For example,embodiments include a valve having three and four leaflets in which eachleaflet has an inner and outer sinus edge, a fan edge, a fan, and acommissure between each neighboring leaflet. For example, athree-leaflet valve may include two commissures: one commissure betweena first leaflet and a second leaflet, and a second commissure betweenthe second leaflet and a third leaflet. Equivalent metrics to thosedescribed above can be used to describe each leaflet of a multi-leafletvalve. The valve may incorporate a closure formed by the juxtaposition,proximity, and/or overlap of three or four fan structures. The mutualdisposition of some portions of the three or four fan edges along withthe inner surface of the conduit may result in a gap similar to the gaparea described above. In some embodiments, the entire valve along withthe leaflets are made from a single piece of biocompatible material asshown in FIG. 10.

The valve described herein is not limited to a particular utility. Forexample, in some embodiments, the valve described herein can be used asheart valves for use in cardiac, coronary or vascular procedures, whichmay be composed of one or more leaflets. The term may encompass, asnon-limiting examples, a heart valve single leaflet having a singleheart valve leaflet, or a heart valve multi-leaflet having more than oneheart valve leaflet. Each heart valve leaflet may include a sinus edge,a fan edge, a sinus structure, and a fan structure, and additionalstructural components such as, without limitation, a conduit (which maybe tube-like, stent-like, or multi-layered such as a tube within astent) and one or more conduit sinus structures. The term may encompassa single leaflet valve having a valve single leaflet structure, or amulti-leaflet valve structure composed of either multiple valve singleleaflet structures or a valve multi-leaflet structure.

In some embodiments, leaflets are constructed from at least one layer ofthe material with each layer having a plurality of pores, with eachindividual pore being defined by a pore area. In some embodiments, theplurality of pores may be disconnected, such that there is limitedcommunication between the pores, separated by a solid node of material.In some embodiments, the plurality of pores have the same pore area. Insome embodiments, the plurality of pores have a different pore area. Insome embodiments, the pore area is about 1 square micron. In someembodiments, the pore area is about 0.5 square micron. In someembodiments, the pore area is about 0.25 square micron. In someembodiments, the pore area is about 0.1 square micron. In someembodiments, the pore area is less than 1 square micron. In someembodiments, the pore area is less than 0.5 square micron. In someembodiments, the pore area is less than 0.25 square micron. In someembodiments, the pore area is less than 0.1 square micron. In someembodiments, the pore area is up to 1 square micron. In someembodiments, the pore area is up to 0.5 square micron. In someembodiments, the pore area is up to 0.25 square micron. In someembodiments, the pore area is up to 0.1 square micron. In someembodiments, the pore area is in a range of about 0.05 square micron toabout 1 square micron. In some embodiments, the pore area is in a rangeof about 0.1 square micron to about 1 square micron. In someembodiments, the pore area is in a range of about 0.25 square micron toabout 1 square micron. In some embodiments, the pore area is in a rangeof about 0.5 square micron to about 1 square micron. In someembodiments, the pore area is in a range of about 0.05 square micron toabout 0.5 square micron. In some embodiments, the pore area is in arange of about 0.05 square micron to about 0.25 square micron. In someembodiments, the pore area is in a range of about 0.05 square micron toabout 0.1 square micron.

In some embodiments, leaflets are constructed from at least one layer ofthe material with a layer having a plurality of pores, with eachindividual pore being defined by a pore area. In some embodiments, theplurality of pores may be disconnected, such that there is limitedcommunication between the pores, separated by a solid node of material.In some embodiments, the plurality of pores have a different pore area.In some embodiments, the plurality of pores having a different pore areaare defined by an average pore area for the material. The average porearea is calculated by adding the pore area of the plurality of pores anddividing by the total number of pores. In some embodiments, the averagepore area is about 1 square micron. In some embodiments, the averagepore area is about 0.5 square micron. In some embodiments, the averagepore area is about 0.25 square micron. In some embodiments, the averagepore area is about 0.1 square micron. In some embodiments, the averagepore area is less than 1 square micron. In some embodiments, the averagepore area is less than 0.5 square micron. In some embodiments, theaverage pore area is less than 0.25 square micron. In some embodiments,the average pore area is less than 0.1 square micron. In someembodiments, the average pore area is up to 1 square micron. In someembodiments, the average pore area is up to 0.5 square micron. In someembodiments, the average pore area is up to 0.25 square micron. In someembodiments, the average pore area is up to 0.1 square micron. In someembodiments, the average pore area is in a range of about 0.05 squaremicron to about 1 square micron. In some embodiments, the average porearea is in a range of about 0.1 square micron to about 1 square micron.In some embodiments, the average pore area is in a range of about 0.25square micron to about 1 square micron. In some embodiments, the averagepore area is in a range of about 0.5 square micron to about 1 squaremicron. In some embodiments, the average pore area is in a range ofabout 0.05 square micron to about 0.5 square micron. In someembodiments, the average pore area is in a range of about 0.05 squaremicron to about 0.25 square micron. In some embodiments, the averagepore area is in a range of about 0.05 square micron to about 0.1 squaremicron.

In some embodiments, leaflets are constructed from at least one layer ofa material having a plurality of pores, with each individual pore beingdefined by a pore diameter. In some embodiments, the plurality of poresmay be disconnected, such that there is limited communication betweenthe pores, separated by a solid node of material. In some embodiments,the plurality of pores have the same pore diameter. In some embodiments,the plurality of pores have a different pore diameter. In someembodiments, the pore diameter is about 1 micron. In some embodiments,the pore diameter is about 0.5 micron. In some embodiments, the porediameter is about 0.25 micron. In some embodiments, the pore diameter isabout 0.1 micron. In some embodiments, the pore diameter is less than 1micron. In some embodiments, the pore diameter is less than 0.5 micron.In some embodiments, the pore diameter is less than 0.25 micron. In someembodiments, the pore diameter is less than 0.1 micron. In someembodiments, the pore diameter is up to 1 micron. In some embodiments,the pore diameter is up to 0.5 micron. In some embodiments, the porediameter is up to 0.25 micron. In some embodiments, the pore diameter isup to 0.1 micron. In some embodiments, the pore diameter is in a rangeof about 0.05 micron to about 1 micron. In some embodiments, the porediameter is in a range of about 0.1 micron to about 1 micron. In someembodiments, the pore diameter is in a range of about 0.25 micron toabout 1 micron. In some embodiments, the pore diameter is in a range ofabout 0.5 micron to about 1 micron. In some embodiments, the porediameter is in a range of about 0.05 micron to about 0.5 micron. In someembodiments, the pore diameter is in a range of about 0.05 micron toabout 0.25 micron. In some embodiments, the pore diameter is in a rangeof about 0.05 micron to about 0.1 micron.

In some embodiments, leaflets are constructed from at least one layer ofa material having a plurality of pores, with each individual pore beingdefined by a pore diameter. In some embodiments, the plurality of poresmay be disconnected, such that there is limited communication betweenthe pores, separated by a solid node of material. In some embodiments,the plurality of pores have a different pore diameter. In someembodiments, the plurality of pores having a different pore area aredefined by an average pore diameter for the material. The average porediameter is calculated by adding the pore diameter of the plurality ofpores and dividing by the total number of pores. In some embodiments,the average pore diameter is about 1 micron. In some embodiments, theaverage pore diameter is about 0.5 micron. In some embodiments, theaverage pore diameter is about 0.25 micron. In some embodiments, theaverage pore diameter is about 0.1 micron. In some embodiments, theaverage pore diameter is less than 1 micron. In some embodiments, theaverage pore diameter is less than 0.5 micron. In some embodiments, theaverage pore diameter is less than 0.25 micron. In some embodiments, theaverage pore diameter is less than 0.1 micron. In some embodiments, theaverage pore diameter is up to 1 micron. In some embodiments, theaverage pore diameter is up to 0.5 micron. In some embodiments, theaverage pore diameter is up to 0.25 micron. In some embodiments, theaverage pore diameter is up to 0.1 micron. In some embodiments, theaverage pore diameter is in a range of about 0.05 micron to about 1micron. In some embodiments, the average pore diameter is in a range ofabout 0.1 micron to about 1 micron. In some embodiments, the averagepore diameter is in a range of about 0.25 micron to about 1 micron. Insome embodiments, the average pore diameter is in a range of about 0.5micron to about 1 micron. In some embodiments, the average pore diameteris in a range of about 0.05 micron to about 0.5 micron. In someembodiments, the average pore diameter is in a range of about 0.05micron to about 0.25 micron. In some embodiments, the average porediameter is in a range of about 0.05 micron to about 0.1 micron.

In some embodiments, leaflets are constructed from a material having athickness. In some embodiments, the thickness is about 0.3 mm. In someembodiments, the thickness is about 0.1 mm. In some embodiments, thethickness is about 0.075 mm. In some embodiments, the thickness is about0.05 mm. In some embodiments, the thickness is about 0.045 mm. In someembodiments, the thickness is about 0.04 mm. In some embodiments, thethickness is about 0.035 mm. In some embodiments, the thickness is about0.03 mm. In some embodiments, the thickness is about 0.025 mm. In someembodiments, the thickness is about 0.02 mm. In some embodiments, thethickness is about 0.015 mm. In some embodiments, the thickness is about0.01 mm. In some embodiments, the thickness is less than 0.3 mm. In someembodiments, the thickness is less than 0.1 mm. In some embodiments, thethickness is less than 0.075 mm. In some embodiments, the thickness isless than 0.05 mm. In some embodiments, the thickness is less than 0.045mm. In some embodiments, the thickness is less than 0.04 mm. In someembodiments, the thickness is less than 0.035 mm. In some embodiments,the thickness is less than 0.03 mm. In some embodiments, the thicknessis less than 0.025 mm. In some embodiments, the thickness is less than0.02 mm. In some embodiments, the thickness is less than 0.015 mm. Insome embodiments, the thickness is less than 0.01 mm. In someembodiments, the thickness is up to 0.3 mm. In some embodiments, thethickness is up to 0.1 mm. In some embodiments, the thickness up to0.075 mm. In some embodiments, the thickness is up to 0.05 mm. In someembodiments, the thickness is up to 0.045 mm. In some embodiments, thethickness is up to 0.04 mm. In some embodiments, the thickness is up to0.035 mm. In some embodiments, the thickness is up to 0.03 mm. In someembodiments, the thickness is up to 0.025 mm. In some embodiments, thethickness is up to 0.02 mm. In some embodiments, the thickness is up to0.015 mm. In some embodiments, the thickness is up to 0.01 mm. In someembodiments, the thickness is in a range of about 0.01 mm to about 0.3mm. In some embodiments, the thickness is in a range of about 0.015 mmto about 0.3 mm. In some embodiments, the thickness is in a range ofabout 0.02 mm to about 0.3 mm. In some embodiments, the thickness is ina range of about 0.025 mm to about 0.3 mm. In some embodiments, thethickness is in a range of about 0.03 mm to about 0.3 mm. In someembodiments, the thickness is in a range of about 0.035 mm to about 0.3mm. In some embodiments, the thickness is in a range of about 0.04 mm toabout 0.3 mm. In some embodiments, the thickness is in a range of about0.01 mm to about 0.1 mm. In some embodiments, the thickness is in arange of about 0.01 mm to about 0.075 mm. In some embodiments, thethickness is in a range of about 0.01 mm to about 0.05 mm. In someembodiments, the thickness is in a range of about 0.015 mm to about0.075 mm. In some embodiments, the thickness is in a range of about 0.02mm to about 0.075 mm. In some embodiments, the thickness is in a rangeof about 0.025 mm to about 0.075 mm. In some embodiments, the thicknessis in a range of about 0.03 mm to about 0.075 mm. In some embodiments,the thickness is in a range of about 0.035 mm to about 0.075 mm. In someembodiments, the thickness is in a range of about 0.04 mm to about 0.075mm. In some embodiments, the thickness is in a range of about 0.045 mmto about 0.075 mm. In some embodiments, the thickness is in a range ofabout 0.01 mm to about 0.05 mm. In some embodiments, the thickness is ina range of about 0.015 mm to about 0.05 mm. In some embodiments, thethickness is in a range of about 0.02 mm to about 0.05 mm. In someembodiments, the thickness is in a range of about 0.025 mm to about 0.05mm. In some embodiments, the thickness is in a range of about 0.03 mm toabout 0.05 mm. In some embodiments, the thickness is in a range of about0.035 mm to about 0.05 mm. In some embodiments, the thickness is in arange of about 0.04 mm to about 0.05 mm. In some embodiments, thethickness is in a range of about 0.045 mm to about 0.05 mm.

In some embodiments, leaflets are constructed from multiple layers of amaterial, wherein the multiple layers of the material have a totalthickness. In some embodiments, the total thickness is about 0.3 mm. Insome embodiments, the total thickness is about 0.1 mm. In someembodiments, the total thickness is about 0.075 mm. In some embodiments,the total thickness is about 0.05 mm. In some embodiments, the totalthickness is about 0.045 mm. In some embodiments, the total thickness isabout 0.04 mm. In some embodiments, the total thickness is about 0.035mm. In some embodiments, the total thickness is about 0.03 mm. In someembodiments, the total thickness is about 0.025 mm. In some embodiments,the total thickness is about 0.02 mm. In some embodiments, the totalthickness is about 0.015 mm. In some embodiments, the total thickness isabout 0.01 mm. In some embodiments, the total thickness is less than 0.3mm. In some embodiments, the total thickness is less than 0.1 mm. Insome embodiments, the total thickness is less than 0.075 mm. In someembodiments, the total thickness is less than 0.05 mm. In someembodiments, the total thickness is less than 0.045 mm. In someembodiments, the total thickness is less than 0.04 mm. In someembodiments, the total thickness is less than 0.035 mm. In someembodiments, the total thickness is less than 0.03 mm. In someembodiments, the total thickness is less than 0.025 mm. In someembodiments, the total thickness is less than 0.02 mm. In someembodiments, the total thickness is less than 0.015 mm. In someembodiments, the total thickness is less than 0.01 mm. In someembodiments, the total thickness is up to 0.3 mm. In some embodiments,the total thickness is up to 0.1 mm. In some embodiments, the totalthickness up to 0.075 mm. In some embodiments, the total thickness is upto 0.05 mm. In some embodiments, the total thickness is up to 0.045 mm.In some embodiments, the total thickness is up to 0.04 mm. In someembodiments, the total thickness is up to 0.035 mm. In some embodiments,the total thickness is up to 0.03 mm. In some embodiments, the totalthickness is up to 0.025 mm. In some embodiments, the total thickness isup to 0.02 mm. In some embodiments, the total thickness is up to 0.015mm. In some embodiments, the total thickness is up to 0.01 mm. In someembodiments, the total thickness is in a range of about 0.01 mm to about0.3 mm. In some embodiments, the total thickness is in a range of about0.015 mm to about 0.3 mm. In some embodiments, the total thickness is ina range of about 0.02 mm to about 0.3 mm. In some embodiments, the totalthickness is in a range of about 0.025 mm to about 0.3 mm. In someembodiments, the total thickness is in a range of about 0.03 mm to about0.3 mm. In some embodiments, the total thickness is in a range of about0.035 mm to about 0.3 mm. In some embodiments, the total thickness is ina range of about 0.04 mm to about 0.3 mm. In some embodiments, the totalthickness is in a range of about 0.01 mm to about 0.1 mm. In someembodiments, the total thickness is in a range of about 0.01 mm to about0.075 mm. In some embodiments, the total thickness is in a range ofabout 0.01 mm to about 0.05 mm. In some embodiments, the total thicknessis in a range of about 0.015 mm to about 0.075 mm. In some embodiments,the total thickness is in a range of about 0.02 mm to about 0.075 mm. Insome embodiments, the total thickness is in a range of about 0.025 mm toabout 0.075 mm. In some embodiments, the total thickness is in a rangeof about 0.03 mm to about 0.075 mm. In some embodiments, the totalthickness is in a range of about 0.035 mm to about 0.075 mm. In someembodiments, the total thickness is in a range of about 0.04 mm to about0.075 mm. In some embodiments, the total thickness is in a range ofabout 0.045 mm to about 0.075 mm. In some embodiments, the totalthickness is in a range of about 0.01 mm to about 0.05 mm. In someembodiments, the total thickness is in a range of about 0.015 mm toabout 0.05 mm. In some embodiments, the total thickness is in a range ofabout 0.02 mm to about 0.05 mm. In some embodiments, the total thicknessis in a range of about 0.025 mm to about 0.05 mm. In some embodiments,the total thickness is in a range of about 0.03 mm to about 0.05 mm. Insome embodiments, the total thickness is in a range of about 0.035 mm toabout 0.05 mm. In some embodiments, the total thickness is in a range ofabout 0.04 mm to about 0.05 mm. In some embodiments, the total thicknessis in a range of about 0.045 mm to about 0.05 mm.

In some embodiments, leaflets are constructed from multiple layers ofmaterial, wherein the multiple layers of material have a totalthickness. In some embodiments, leaflets are constructed from multiplelayers of material, where the layers are substantially similar inthickness. In other embodiments, leaflets are constructed from multiplelayers of material were the layers differ significantly in thickness.For example, a leaflet may be constructed from two layers, one of whichis approximately 0.040 mm thick, and another is approximately 0.005 mmthick, resulting in a total thickness of 0.045 mm.

As illustrated in FIG. 13, in some embodiments leaflets are constructedfrom a material having a surface porosity. In some embodiments, thesurface porosity may range up to 15%, but not be less than 1%. In someembodiments, the surface porosity is about 15%. In some embodiments, thesurface porosity is about 14%. In some embodiments, the surface porosityis about 13%. In some embodiments, the surface porosity is about 12%. Insome embodiments, the surface porosity is about 11%. In someembodiments, the surface porosity is about 10%. In some embodiments, thesurface porosity is about 9%. In some embodiments, the surface porosityis about 8%. In some embodiments, the surface porosity is about 7%. Insome embodiments, the surface porosity is about 6%. In some embodiments,the surface porosity is about 5%. In some embodiments, the surfaceporosity is about 4%. In some embodiments, the surface porosity is about3%. In some embodiments, the surface porosity is about 2%. In someembodiments, the surface porosity is about 1%. In some embodiments, thesurface porosity is less than 15%. In some embodiments, the surfaceporosity is less than 14%. In some embodiments, the surface porosity isless than 13%. In some embodiments, the surface porosity is less than12%. In some embodiments, the surface porosity is less than 11%. In someembodiments, the surface porosity is less than 10%. In some embodiments,the surface porosity is less than 9%. In some embodiments, the surfaceporosity is less than 8%. In some embodiments, the surface porosity isless than 7%. In some embodiments, the surface porosity is less than 6%.In some embodiments, the surface porosity is less than 5%. In someembodiments, the surface porosity is less than 4%. In some embodiments,the surface porosity is less than 3%. In some embodiments, the surfaceporosity is less than 2%. In some embodiments, the surface porosity isin a range of about 1% to about 15%. In some embodiments, the surfaceporosity is in a range of about 2% to about 15%. In some embodiments,the surface porosity is in a range of about 3% to about 15%. In someembodiments, the surface porosity is in a range of about 4% to about15%. In some embodiments, the surface porosity is in a range of about 5%to about 15%. In some embodiments, the surface porosity is in a range ofabout 6% to about 15%. In some embodiments, the surface porosity is in arange of about 7% to about 15%. In some embodiments, the surfaceporosity is in a range of about 8% to about 15%. In some embodiments,the surface porosity is in a range of about 1% to about 14%. In someembodiments, the surface porosity is in a range of about 1% to about13%. In some embodiments, the surface porosity is in a range of about 1%to about 12%. In some embodiments, the surface porosity is in a range ofabout 1% to about 11%. In some embodiments, the surface porosity is in arange of about 1% to about 10%. In some embodiments, the surfaceporosity is in a range of about 1% to about 9%. In some embodiments, thesurface porosity is in a range of about 1% to about 8%. In someembodiments, the surface porosity is in a range of about 1% to about 7%.In some embodiments, the surface porosity is in a range of about 1% toabout 6%. In some embodiments, the surface porosity is in a range ofabout 1% to about 5%. In some embodiments, the surface porosity is in arange of about 1% to about 4%. In some embodiments, the surface porosityis in a range of about 1% to about 3%. In some embodiments, the surfaceporosity is in a range of about 1% to about 2%. In some embodiments, thesurface porosity is in a range of about 1% to about 8%. In someembodiments, the surface porosity is in a range of about 2% to about 8%.In some embodiments, the surface porosity is in a range of about 3% toabout 8%. In some embodiments, the surface porosity is in a range ofabout 4% to about 8%. In some embodiments, the surface porosity is in arange of about 1% to about 7%. In some embodiments, the surface porosityis in a range of about 1% to about 6%. In some embodiments, the surfaceporosity is in a range of about 1% to about 5%. In some embodiments, thesurface porosity is in a range of about 1% to about 4%. In someembodiments, the surface porosity is in a range of about 1% to about 3%.In some embodiments, the surface porosity is in a range of about 1% toabout 2%. In some embodiments, the surface porosity is in a range ofabout 2% to about 6%. In some embodiments, the surface porosity is in arange of about 3% to about 5%. In some embodiments, the surface porosityis in a range of about 1% to less than 15%.

In some embodiments, leaflets are constructed from multiple layers ofmaterial, at least two layers of which are anisotropic with differingorientations. For example, in some embodiments, two layers may beanisotropic with orientations that are perpendicular to one another. Inother embodiments, two layers may be anisotropic with orientations thatare offset by less than 90 degrees, but greater than 10 degrees,relative to each other. In some embodiments, two layers may beanisotropic with orientations that are not parallel relative to eachother. In some embodiments, two layers may be anisotropic withorientations that are offset by about 90 degrees to about 10 degrees,about 85 degrees to about 10 degrees, about 80 degrees to about 10degrees, about 75 degrees to about 10 degrees, about 70 degrees to about10 degrees, about 65 degrees to about 10 degrees, about 60 degrees toabout 10 degrees, about 55 degrees to about 10 degrees, about 50 degreesto about 10 degrees, about 45 degrees to about 10 degrees, about 40degrees to about 10 degrees, about 35 degrees to about 10 degrees, about30 degrees to about 10 degrees, about 25 degrees to about 10 degrees,about 20 degrees to about 10 degrees, about 15 degrees to about 10degrees relative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 90 degrees toabout 15 degrees, about 90 degrees to about 20 degrees, about 90 degreesto about 25 degrees, about 90 degrees to about 30 degrees, about 90degrees to about 35 degrees, about 90 degrees to about 40 degrees, about90 degrees to about 45 degrees, about 90 degrees to about 50 degrees,about 90 degrees to about 55 degrees, about 90 degrees to about 60degrees, about 90 degrees to about 65 degrees, about 90 degrees to about70 degrees, about 90 degrees to about 75 degrees, about 90 degrees toabout 80 degrees, about 90 degrees to about 85 degrees relative to eachother. In some embodiments, two layers may be anisotropic withorientations that are offset by about 90 degrees relative to each other.In some embodiments, two layers may be anisotropic with orientationsthat are offset by about 85 degrees relative to each other. In someembodiments, two layers may be anisotropic with orientations that areoffset by about 80 degrees relative to each other. In some embodiments,two layers may be anisotropic with orientations that are offset by about75 degrees relative to each other. In some embodiments, two layers maybe anisotropic with orientations that are offset by about 70 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 65 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 60 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 55 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 50 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 45 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 40 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 35 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 30 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 25 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 20 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 15 degreesrelative to each other. In some embodiments, two layers may beanisotropic with orientations that are offset by about 10 degreesrelative to each other.

Disclosed herein are transcatheter stents with valved conduits. Anexemplary stent is shown in FIG. 9A. The stent 900 has three contiguousportions or regions, a proximal portion 901, an intermediate portion902, and a distal portion 903. The proximal portion 901 has a relativelylarger cross-section in the expanded configuration, while theintermediate portion 902 and the distal portion 903 have relativelysmaller cross-section in the expanded configuration. The intermediateportion 902 is in the form of a cylinder having a substantially constantdiameter along its length. In some embodiments, the intermediate portion902 may have a variable diameter along its length. A transition section901 a may taper inwardly from the proximal portion 901 to theintermediate portion 902. Further, the proximal portion 901 faces theaorta and the distal portion 903 faces the annulus when the stent isdeployed.

In some embodiments, proximal portion 901 and the distal portion 903 ismade of a series of cells arranged in one or more annular rows aroundthe stent. The cells may be spindle-shaped structures 904 as shown inFIG. 9A, and may be defined as structures having a wider central sectionwith tapering ends. For example, in FIG. 9A the proximal portion 901 andthe distal portion 903 are each made up of two annular rows of spindleshaped structures. In other embodiments, proximal portion 901 and thedistal portion 903 may each have three, or four, or five annular rows ofspindle shaped structures. It should be appreciated that as the numberof annular rows increase, the area formed by each spindle shapedstructure may decrease correspondingly, to maintain the length of theproximal portion 901 and the distal portion 903. Further, the area ofspindle shaped structures in the proximal portion 901 may be larger thanthe area of spindle shaped structures in the distal portion 903. It willbe appreciated that the shape of the cells are not limited to spindleshaped structures, and can also encompass other shapes such as diamondshapes, rhomboid shapes, and the like.

In some embodiments, the intermediate portion 902 is made of a series ofchevron shaped structures 905 arranged in two or more annular rowsopposing to each other. For clarity, an isolated pair of opposingchevron shaped structures are depicted in FIG. 9B. For example, in FIG.9A, the intermediate portion 902 has two annular rows 902 a, 902 b ofchevron shaped structures 905 opposing each other. Row 902 a is towardsthe proximal portion 901, and row 902 b is towards the distal portion903. The number of chevron shaped structures 905 in each annular row mayvary. For example, in FIG. 9A there are 12 chevron shaped structures 905in each annular row 902 a, 902 b. In other embodiments, the number ofchevron shaped structures 905 in each annular row may vary from 4 to 24.

In some embodiments, the intermediate portion 902 of the stent 900further has one or more attachment points 906 to facilitate attachmentof the conduit and/or the valve structure, as shown in FIG. 9A. Theattachment points 906 are present on the median vertices of one or morechevron shaped structures 905. For example, FIG. 9C shows a singlechevron shaped structure 905 with a pair of median vertices 906 a, 906b, and a pair of lateral vertices 907 a, 907 b. Proximal median vertex906 a faces towards the proximal portion 901 of the stent, and distalmedian vertex 906 b faces towards the distal portion 903 of the stent.Preferably, the conduit and/or the valve structure may be attached tothe proximal and distal median vertices (906 a, 906 b) of the chevronshaped structures 905 present in the intermediate portion 902 of thestent. The number of attachment points may vary, ranging from 6 to 20,depending on the size of the stent and the conduit/valve structure. Theconduit and/or the valve structure may be attached to the attachmentpoints 906 by suturing, welding, fusion, applying an adhesive, andcombinations thereof. The attachment points 906 are disposed at aselected distance between each other such that the distance between theattachment points do not substantially change when the stent iscollapsed (crimped) from an expanded configuration.

In FIG. 9D and FIG. 9E, the stent 900 in FIG. 9D is shown in expandedconfiguration with a plurality of attachment points 906 a, 906 b, 906 c,and 906 d in the intermediate portion 902. When the stent 900 b iscollapsed (FIG. 9E), the distance between the attachment points 906 aand 906 b, between attachment points 906 c and 906 d, and betweenattachment points 906 b and 906 c essentially remain the same.Attachment points 906 c and 906 d rotate with respect to 906 a and 906 band compensates for the longitudinal stretching of the stent. Inaddition, 906 a and 906 b translate together and 906 c and 906 dtranslate together in opposite directions. Therefore, although theintermediate portion 902 changes length when it undergoes the transitionfrom expanded configuration to the collapsed configuration, the lengthof multiple regions (in this example 906 a-906 b, 906 b-906 c, and 906c-906 d) remain substantially the same.

Due to the non-stretching nature of the portions of the stent, it canaccommodate conduits and valve structures made of non-stretch material.Non-limiting examples of non-stretch material that can be used to makethe conduits and valve structures are polytetrafluoroethylene (PTFE),expanded polytetrafluoroethylene (ePTFE), polyethylene terephthalate(PET), polydimethyl siloxane (PDMS), polyethylene (PE), polypropylene(PP), polyesters, polycarbonates, polyvinyl chloride (PVC), hydrogels, amethacrylate polymer, a vinyl benzene polymer, a 2-hydroxyethyl acrylatepolymer, a butyl acrylate polymer, a 2-ethylhexyl acrylate polymer, avinyltrimethoxysilane polymer, a vinyltriethoxysilane polymer, avinyltoluene polymer, an cc-methyl styrene polymer, a chlorostyrenepolymer, a styrenesulfonic acid polymer, and a combination thereof.

The stent disclosed herein may be made from cobalt, titanium, nickel,chromium, stainless steel, a polymer, a pseudo-elastic metal, and alloysthereof, and any combination thereof. In some embodiments, the stent maybe made from nickel titanium alloy nitinol. In some embodiments, thestents disclosed herein are self-expandable stents. Self-expandablestent as used herein means that a structure/component has a mechanicalmemory to return to the expanded or deployed configuration. Mechanicalmemory may be imparted to the framework structure that forms stent bythermal treatment to achieve a spring temper in stainless steel, forexample, or to set a shape memory in a susceptible metal alloy, such asnitinol, or a polymer.

It will be understood by one of ordinary skill in the art that thelength of each portion of the stent 900 may vary according toapplication and is not limited to the proportions shown in FIG. 9A. Forexample, in one embodiment the length of the intermediate portion 902 isequal to the length of the leaflet of a valve structure describedherein, for example length B of leaflet 701 as shown in FIG. 7D. In someembodiments, the length of the intermediate portion 902 is such that thedistance between the two attachment points 906 a and 906 c is equal tothe length B of the leaflet 701 shown in FIG. 7D. In some embodiments,the length of the intermediate portion 902 may be about 5 mm to about 40mm, about 5 mm to about 30 mm, about 8 mm to about 25 mm, about 10 mm toabout 20 mm, and ranges between them. In some embodiments, the length ofthe proximal portion 901 may be from about 5 mm to about 50 mm, about 5mm to about 40 mm, about 5 mm to about 30 mm, about 5 mm to about 20 mm,about 25 mm to about 50 mm, or about 35 mm to about 50 mm. In someembodiments, the distal portion 903 may have a length of about 3 mm toabout 20 mm, about 3 mm to about 15 mm, about 3 mm to about 10 mm, orabout 3 mm to about 5 mm or a value within any of these ranges. Itshould be appreciated that the length described herein of variousportions may not vary irrespective of whether the stent is in expandedconfiguration (deployed state) or collapsed configuration (crimpedstate).

In some embodiments, the diameter of the proximal portion 901 may befrom about 5 mm to about 50 mm, about 5 mm to about 40 mm, about 5 mm toabout 30 mm, about 5 mm to about 20 mm, about 5 mm to about 10 mm, orany individual width or range encompassed by these example widths. Insome embodiments, the proximal portion 901 of the stent may havesubstantially constant diameter along its length. In some embodiments,the proximal portion 901 may taper inwardly towards the intermediateportion 902.

In some embodiments, the diameter of the intermediate portion 902 may befrom about 5 mm to about 50 mm, about 5 mm to about 40 mm, about 5 mm toabout 30 mm, about 5 mm to about 20 mm, about 5 mm to about 10 mm, orany individual width or range encompassed by these example widths. Insome embodiments, the intermediate portion 902 of the stent may havesubstantially constant diameter along its length. In some embodiments,the intermediate portion 902 may have variable diameter along itslength.

In some embodiments, the diameter of the distal portion 903 may be fromabout 5 mm to about 50 mm, about 5 mm to about 40 mm, about 5 mm toabout 30 mm, about 5 mm to about 20 mm, about 5 mm to about 10 mm, orany individual width or range encompassed by these example widths. Insome embodiments, the distal portion 903 of the stent may havesubstantially constant diameter along its length. In some embodiments,the free edge of the distal portion 903 may taper outward.

FIG. 10 illustrates an embodiment of a valve structure 1000 that may beattached to the stent 900. The valve 1000 is made of a single piece ofbiocompatible material, having 3 leaflets 1001. A commissure 1002 existsbetween each leaflet. The outer sinus edge and inner sinus edge of eachleaflet can be attached to the intermediate portion 902 of the stent. Insome embodiments, each leaflet of the valve is attached to theintermediate portion 902 at a pair of attachment points, and eachattachment point present on opposing annular row of chevron shapedstructures. For example, the regions 1000 a-c on the valve may beattached to the attachment points 906 a-c present on the intermediateportion of the stent, as shown in FIG. 9D. For example, 1000 a isattached to 906 a, 1000 b is attached to 906 b, and 1000 c is attachedto 906 c. Because the distance between the attachment points 906 a-906 band 906 b-906 c do not change when the stent is expanded or collapsed, avalve made from a non-stretchable material may be used. In addition,other regions of the leaflet can also be used to attach the valve to thestent, such as the commissure region 1002. In some embodiments, thevalve is directly attached to the stent. In other embodiments, the valveis attached to the inner surface of a conduit, and the conduit isattached to the stent. In further embodiments, the valve and the conduitare concurrently attached to the same regions of the stent.

In some embodiments, the stent includes a valved conduit (a conduithaving valve). In other embodiments, the stent includes a valve directlyattached to the stent. FIG. 11A and FIG. 11B show an exemplaryembodiment of stent 1100 having a conduit 1101 disposed on an innersurface of the stent 1100, and a valve 1102. In some embodiments, thevalve 1102 may be attached directly to the inner surface of the stent1100, without conduit 1101 disposed between the valve and the stent. Inanother embodiment, a sheath may also be located on the outer surface ofthe stent. The conduit and/or the sheath may cover all or only a portionof the length and circumference of the stent. Further, the valvecontained within the stents of such embodiments can have any number ofleaflets. For example, the stent 1100 in FIG. 11B has three leaflets;however, embodiments include stents with valves having two leaflets asillustrated in FIG. 2B and FIG. 3B or one leaflet as illustrated in FIG.1A. Similarly, the valved conduits described above and exemplified inFIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, FIG. 3A, FIG. 3B can include threeleaflets. Each leaflet of the stent 1100 of various embodiments mayinclude a gap when the valve is in open position (FIG. 11A) andtherefore, may have a width that is shorter than the portion of theconduit between attachment points.

Various embodiments are directed to a fixing stencil 840. In someembodiments as illustrated in FIG. 8A and FIG. 8B, the fixing stencil840 may include a stencil head 841 and handle 842. The stencil head 841may substantially triangular flat surface 843 having a base 844, a firstouter edge 845, a second outer edge 846, and a tip 847, and a triangularcurved surface 848. In various embodiments, the triangular curvedsurface 848 may be tapered laterally from a longitudinal axis extendingfrom the handle 842 to first outer edge 845 and from the longitudinalaxis to the second outer edge 847. The triangular curved surface 848 maybe further curved from the base 844 to the tip 847 creating a complex ofcurved surfaces having a tetrahedral shape extending away from the base844 to the tip 847. In some embodiments, the stencil head 841 mayfurther include holes or slots 849 along the first outer edge 845 andsecond outer edge 846 to allow physical fixturing, for example,suturing, welding, adhesive application, or other means for attachingthe leaflet 801 to the conduit 80 without contacting the stencil head841. In other embodiments, the stencil head 841 may be pierceable orlocally destructible along the first outer edge 845 and second outeredge 846 to allow removal of the stencil head 841 after fixturing.

The handle 842 of various embodiments may be any means for manipulatingand holding the fixing stencil 840 in place while the valve is attachedto the conduit. For example, in some embodiments, the handle may besized and shaped to be gripped by a human hand. In other embodiments,the handle may be include one or more tabs or wings sized and shaped forholding the fixing stencil to the conduit and valve using surgicaltools, claps, vice grips, or other tools.

The size of the stencil head 841 may vary depending on the size andshape of the valve to 8 that will be produced using the fixing stencil840. In general, the length, B_(s), from the base 844, extending fromthe handle, to the tip 845, of the stencil head 841 may be substantiallythe same length, B, as the leaflet 801. The variable width, W_(SL), ofthe substantially triangular flat surface may substantially correspondto the variable width of the triangular leaflet and the variable depth,D_(SL), of the triangular curved surface 884 may substantiallycorresponding to the depth of the sinus 830. Thus, the stencil head maybe configured to have substantially the same shape and volume as thesinus 830 created between the leaflet 801 and the portion of the conduit80 making up the tapered dimple 85.

In various embodiments, the width, W_(SL), of the stencil head 841 maybe about 1 mm to about 10 mm, about 2 mm to about 7 mm, about 2 mm toabout 5 mm, about 20 mm to about 40 mm, about 10 mm to about 30 mm, orany individual width or range encompassed by these example widths. Thelength, B_(S), of the stencil head 841 may be about 5 mm to about 40 mm,about 5 mm to about 30 mm, about 8 mm to about 25 mm, about 10 mm toabout 20 mm, or any individual length or range encompassed by theseexample lengths. The length of the first outer edge 845 and second outeredge 846 may each, individually, be about 5 mm to about 45 mm, about 5mm to about 35 mm, about 8 mm to about 30 mm, about 10 mm to about 20mm, or any individual length or range encompassed by these examplelengths. The depth, D_(SL), of the stencil head 841 at the base 844 maybe about 1 mm to about 10 mm, about 1 mm to about 7 mm, about 1 mm toabout 5 mm, or any individual depth or range encompassed by theseexample depths.

In some embodiments, the fixing stencil 840 may further includestabilizing components the stencil head 841 during fixturing. Forexample, the stabilizing components may include a clamp positioned tohold the tapered dimple 85 or an apparatus that substantially fills theremainder of the conduit. In certain embodiments, the stencil head 841may be capable of transmitting heat to the conduit to aid in fixturingby fusing the leaflet 801 to the conduit 80 or aiding in deformation ofthe conduit 80 creating a sinus bulge at the sinus when the fixingstencil 840 is removed.

Further embodiments are directed to methods for making the valvedconduits described above. Such embodiments may include the steps ofinverting a conduit, bending a portion of the conduit to create atapered dimple, attaching a leaflet to the conduit on a surfacesurrounding the tapered dimple, and reverting the conduit placing theleaflet on an inner surface of the conduit. The step of attaching can becarried out by suturing, welding, fusing, using an adhesive, and thelike or combinations thereof. In some embodiments, the method mayfurther include the step of deforming the conduit to produce a sinusbulge. In some embodiments, bending can be carried out using a fixingstencil configured to hold conduit in a bent form creating a tapereddimple. The fixing stencil may have substantially the same shape as thetapered dimple. In various embodiments, the fixing stencil may have oneor more of the parts described above.

In some embodiments, a method of making a valve may include the step ofcutting a valve structure from a biocompatible material. In certainembodiments, the step of cutting the valve structure may be preceded bya step of marking the biocompatible material, and in some embodiments,marking may be carried out by tracing a valve structure stencil havingsubstantially the same shape as the valve structure onto thebiocompatible material. In other embodiments, the marking can be carriedout using a stamp having substantially the same shape as the valvestructure. In still other embodiments, step of cutting can be carriedout using a die cutting machine. Where the leaflets of the valvecomprise more than one layer of the material, in some embodiments, twoor more layers of the material may be attached to each other. In someembodiments, the two or more layers may be attached through one or moreof the following: physical connections, such as sutures or clamps,welding, sintering, heating, such as applied heat through one or moreplates, single or concentric cylinders, or laser, chemical welding,adhesive, static electric or frictional forces. For purposes of thisdisclosure, in embodiments where the layers of the material are attachedto make the leaflet but distinction between the layers has been lost,such leaflet should still be considered to have more than one layer.

In some embodiment, the method of making a valved conduit may furtherinclude the step of marking an inner surface of the conduit with alocation form attaching the leaflet to the conduit, thereby providingproper placement and alignment of the leaflets. Marking can be carriedout by various means. For example, in some embodiments, marking can becarried out using a sinus stencil may be provided, and the marking onthe inner surface of the conduit can be substantially the same as thesinus stencil. In such embodiments, the sinus stencil may have a shapeand dimension for showing the location of the tapered dimple on theunbent inner surface of the conduit. Therefore, the sinus stencil may bewider than the valve structure, but the markings may have essentiallythe same shape as the leaflet after the conduit is bent.

EXAMPLE 1

The objective of the study was to compare the microstructure andmaterial properties of a multi-layer leaflet (termed PECA or PECALeaflet Material) according to some embodiments described above to amulti-layer leaflet currently marketed (termed Gore or Gore PrecludeMembrane having a total average thickness of 0.1 mm). According to someembodiments described above, the PECA Leaflet Material comprises amulti-layer leaflet made of ePTFE having a total thickness of 0.045 mm,wherein the multi-layers of the leaflet are anisotropic withorientations that are offset by less than 90 degrees, but greater than10 degrees, relative to each other. The PECA Leaflet Material, depictedin FIG. 14B (side A) and FIG. 14D (side B), has a reduction in surfacepercent porosity when compared to Gore, depicted in FIG. 14A (side A)and FIG. 14C (side B). The quantification of these data are illustratedin FIG. 14E.

Under similar conditions described above, and when compared to Gore, thePECA Leaflet Material has improved ultimate tensile stress in both theX-direction (dark bars) and Y-direction (gray bars) as illustrated inFIG. 15A, improved burst pressure as illustrated in FIG. 15B, improvedsuture retention strength in both the X-direction (dark bars) andY-direction (gray bars) as illustrated in FIG. 15C, and improved sutureretention in a 45 degree orientation as illustrated in FIG. 15D.Additionally, when compared to Gore, the PECA Leaflet Material displaysaugmented bending modulus measured in MPa as illustrated in FIG. 16A,and no change in bending modulus measured in N mm² (which accounts forthe Moment of Inertia) as illustrated in FIG. 16B. The PECA LeafletMaterial further displays reduced membrane tension compared to Gore asdepicted in FIG. 17A, and reduced stress as depicted in FIG. 17B.

EXAMPLE 2

The objective of the study was to assess the thrombogenic properties ofthe PECA Leaflet Material as described in Example 1 and compare it tothe Gore commercially available membrane material that is intended toresist thrombosis.

The PECA Leaflet Material comprises a multi-layer leaflet made of ePTFEhaving a surface porosity of about 4% (about 2% of Side A and about 6%on side B), a total thickness of 0.045 mm, wherein the multi-layers ofthe leaflet are anisotropic with orientations that are rotated by lessthan 90 degrees, but greater than 10 degrees, relative to each other.The PECA Leaflet Material was compared to the Gore Preclude Membranehaving a total thickness of 0.1 mm in a blood-contacting environment. Inorder to compare and assess the differential activated platelet andfibroblast growth on the material, multiple samples (n=3) of eachmaterial were cut into 1×1 cm pieces and prepared for blood exposure in2 ml Centrifuge tubes and weighed. Sheep blood was then treated with 0.5units of heparin per mL of blood. The blood was then re-calcified usingCalcium Chloride and an arterial blood gas analyzer was used to readcalcium levels until a reading of 1-1.5 mmol/L was attained. This bloodwas added to the 2 mL centrifuge tubes with the different materials tobe tested & filled to top to avoid the presence of air. The tubes placedon a rocker at 37° C. All samples were removed after 15 mins ofincubation and were rinsed for 5 minutes five times. The first rinse waswith 100 units/mL heparin solution in saline, and the other four rinsingprocedures were performed with saline. These samples were then collectedand prepared appropriately for visualization under Scanning ElectronMicroscopy (SEM) and a qualitative analysis was performed.

A significantly lower amount of activated platelet adhesion andfibroblastic activity was observed in the PECA Leaflet Material (FIG.18A depicts Side A, low magnification; FIG. 18C depicts Side A, highmagnification; FIG. 18B depicts Side B, low magnification; FIG. 18Ddepicts Side B, high magnification) when compared to Gore (FIG. 18Edepicts Side A, low magnification; FIG. 18G depicts Side A, highmagnification; FIG. 18F depicts Side B, low magnification; FIG. 18Hdepicts Side B, high magnification).

The SEM images confirm the PECA Leaflet Material displays improvedmicrostructure and material properties and is more resistant tothrombosis compared to the Gore Preclude Membrane. It was concludedqualitatively that the PECA Leaflet Material showed little or no signsof thrombosis or fibrotic growth as the material itself was visiblethroughout the image without signs of platelets, fibrin, or cells. TheGore materials showed significant amounts of activated platelet growthalong with fibrous growth seen as a result of thrombosis of blood on thematerial.

EXAMPLE 3

A method of making a conduit, valve, or leaflet having a multiple layersof material is exemplified below. The inner surface of a first layer ofmaterial is superposed to the outer surface of a second layer ofmaterial. The first layer and the second layer are attached by providingheat beyond the melting temperature of at least one of the first layeror the second layer. The melting temperature of at least one of thefirst layer or the second layer may be determined by routineexperimentation of one skilled in the art.

Alternatively, a plate is provided to support the first layer ofmaterial when superposed to the second material. Heat is then provided,beyond the melting temperature of at least one of the first layer or thesecond layer, to attach the first layer and the second layer. Followingremoval of the plate and heat, the multiple layers of material may beformed into a conduit, a valve, or a leaflet by any cutting method knownin the art. Non-limiting examples of cutting methods include the use ofscissors, a blade, die cutting, laser cutting or combinations thereof.

For example, a valved conduit may be made by extruding two tubularlayers, and then placed such that there is an outer and inner concentriclayer. An inner and an outer concentric cylindrical fixture are placedand heated to beyond the melting temperature of at least one layer.

Leaflets may be made by cutting the tubular layers and placing them toform sheets, one lying on top of the other. Plates are placedsandwiching the two layers and heat is applied beyond the meltingtemperature of at least one layer. When the plates or heating cylindersare removed, the layers are sintered and may be formed into leaflets byhand (with scissors, blade, etc.), by die cut, by laser cut, or thelike.

EXAMPLE 4

The objective of the study was to assess the luminal and abluminalsurface thrombogenic properties of a multi-layer conduit (termed PECAConduit) as described above. The luminal surface of the multi-layerconduit has a surface porosity of less than 10%, and the abluminalsurface of the multi-layer conduit has a surface porosity of greaterthan 20%. The multi-layer conduit is compared to the Gore commerciallyavailable membrane material that is intended to resist thrombosis, and aBARD Impra Conduit commercially available graft that is intended toallow some thrombosis.

The PECA Conduit comprises a multi-layer conduit made of ePTFE having aluminal surface porosity of about 4%, an abluminal surface porosity ofgreater than 20%, a total luminal-layer thickness of 0.045 mm, and atotal abluminal layer thickness of about 1 mm. The PECA Conduit wascompared to the Gore Preclude Membrane having a total thickness of 0.1mm in a blood-contacting environment and the BARD Impra Conduit having asurface porosity of >20%. In order to compare and assess thedifferential activated platelet and fibroblast growth on the material,multiple samples (n=3) of each material were cut into 1×1 cm pieces andprepared for blood exposure in 2 ml Centrifuge tubes and weighed. Sheepblood was then treated with 0.5 units of heparin per mL of blood. Theblood was then re-calcified using Calcium Chloride and an arterial bloodgas analyzer was used to read calcium levels until a reading of 1-1.5mmol/L was attained. This blood was added to the 2 mL centrifuge tubeswith the different materials to be tested & filled to top to avoid thepresence of air. The tubes placed on a rocker at 37° C. All samples wereremoved after 15 mins of incubation and were rinsed for 5 minutes fivetimes. The first rinse was with 100 units/mL heparin solution in saline,and the other four rinsing procedures were performed with saline. Thesesamples were then collected and prepared appropriately for visualizationunder Scanning Electron Microscopy (SEM) and a qualitative analysis wasperformed.

A significantly lower amount of activated platelet adhesion andfibroblastic activity was observed in the luminal surface of the PECAConduit (FIG. 19A) when compared to the Gore Preclude Membrane (FIG.19C). Higher amounts of growth were seen on both the abluminal surfaceof the PECA Conduit (FIG. 19B) and BARD Impra Conduit (FIG. 19D).

The SEM images confirm the PECA Conduit displays a luminal surface thatfeatures improved microstructure and material properties and is moreresistant to thrombosis compared to the Gore Preclude Membrane, whilemaintaining an abluminal surface which is less resistant to thrombosisthan Gore Preclude Membrane. It was concluded qualitatively that thePECA Conduit luminal surface showed little or no signs of thrombosis orfibrotic growth as the material itself was visible throughout the imagewithout signs of platelets, fibrin, or cells, while the abluminalsurface did allow for some thrombosis and/or fibrotic growth. The GorePreclude Membrane materials showed a small amount of thrombosis, whilethe BARD Impra Conduit showed the most thrombosis.

What is claimed is:
 1. An conduit suitable for implantation into a humanor animal, the conduit comprising at least two layers, wherein at leastone layer comprises a material having a surface porosity of 1.9% to lessthan 15%.
 2. The conduit of claim 1, wherein at least one layer isplastically deformable.
 3. The conduit of claim 1, wherein at least onelayer comprises a fluoropolymer.
 4. The conduit of claim 1, wherein atleast one layer has a surface coating.
 5. The conduit of claim 1,wherein at least one layer is anisotropic.
 6. The conduit of claim 1,wherein the at least two layers are anisotropic.
 7. The conduit of claim1, wherein at least one layer has an average pore area of less than orabout 1 square micron.
 8. The conduit of claim 1, wherein at least onelayer has an average pore diameter of less than or about 1 micron. 9.The conduit of claim 1, wherein at least one layer has a thickness ofless than or about 0.1 mm.
 10. The conduit of claim 1, wherein at leastone layer is generally aligned along an axial direction of the conduit.11. The conduit of claim 1, wherein the at least two layers have a totalthickness of less than or about 0.1 mm.
 12. The conduit of claim 1,wherein at least one layer has a suture retention strength from about320 g to about 1,172 g.
 13. The conduit of claim 1, wherein the at leasttwo layers are separably manufacturable.
 14. A conduit suitable forimplantation into a human or animal, the conduit comprising at leastthree layers, wherein at least two layers comprise a material having asurface porosity of 1.9% to less than 15%, and wherein at least twolayers have orientations that are offset by an angle of at least 10degrees relative to each other.
 15. The conduit of claim 14, wherein theangle is from about 10 degrees to about 90 degrees.